1. Field of the Invention
The present invention relates to a transparent display apparatus and a method for controlling the same, and more particularly, to a transparent display apparatus and a method forgiving a stereoscopic effect to an image displayed on the transparent display apparatus.
2. Description of the Related Art
Transparent display apparatus allows the user to see both the image displayed from the display apparatus and the background view behind the display apparatus. Attempts have been made to provide such transparent display apparatus with a liquid-crystal display (LCD). However, the two polarizing plates included in the liquid-crystal display significantly reduced the transmittance rate through the display device. In addition, the back-light unit and/or various optical sheets, such as a diffuser sheet or a prism sheet, made it extremely difficult to obtain sufficient transparency through the LCD based transparent display device.
Display devices employing organic light-emitting diode (OLED) do not require such polarizing plates as the LCD display device. Also the back-light unit is not required as the OLED is a self-emissive device. For these reasons, the OLED based display device is considered as the promising component in implementing a transparent display apparatus.
A transparent display is a display that shows a view behind of a display through the display itself. When using the transparent display apparatus, the user recognizes the image as a front space and the view behind the display apparatus as a back space. That is, the user recognizes the depth of two different spaces. This makes the transparent display apparatus a suitable display device for displaying contents having stereoscopic effect, for example, augmented reality contents or any interactive contents incorporating the surrounding environment. On the other hand, when the amount of the external light through the display apparatus is greater than amount of the light of the image displayed by the device itself, the quality of the image is degraded. In other words, a contrast ratio and a color saturation of the image are reduced by the view, which is essentially the external light ray from the rear side of the transparent display apparatus, thereby making it difficult for the user to recognize the depth of the individual objects of the image. That is, the quality of the image is degraded in terms of stereoscopic effect.
Even with such improvement in transparency, there remains a challenge in providing a transparent display apparatus capable of providing improved user experience.